Precision lamp adapter



July 7, 1936. E w BEGGS 2,046,363

PRECISION LAMP ADAPTER Filed June 2'7, 1955 INVENTOR 16 E. M 55666 1 ATTORNE WWW Patented July 7, 1936 UNITED STATES PATENT OFFICE Westinghouse Lamp of Pennsylvania Company, a corporation Application June 27, 1933, Serial No. 677,810

4 Claims. (01. 17c 32) This invention relates to an electric incandescent lamp and socket and relates particularly to an adapter for holding a projection lamp in a socket.

The commercial type of projection lampextensively used is constructed withprojections in the form of fins or pins which extend from the cylindrical wall of what may be termed a secondary or auxiliary base. In practice a lamp is 10 made with the usual type of base which is positioned with the usual commercial accuracy. Another base having fins or pins projecting therefrom is applied to the first base and secured by solder in such position that the fins are a definite 15 distance from the light source. These pins or fins serve in conjunction with a socket to position the light source in a predetermined position with re-- spect to a reflector when the lamp is in a projection unit. The use of fins orpins positioned as 20 above described is well known in the lamp art and the present invention aims to utilize such type of lamp in projection equipment designed for holding a lamp having a difierent structure. For example, Patent 1,675,554 to Howell, issued July, 25 1928 discloses a form of projection lamp housing which requires a lamp having a special base construction. The base of a lamp to be used in the unit disclosed in this patent includes an annulus which is soldered on a screw base a definite dis-' 30 tance from the-light source. The attachment of an annulus to a base necessitates a somewhat laborious as well as a costly operation as compared to the use of an auxiliary base on standard projection lamps in wide commercial use.

35 The use of housings, such as shown in the above mentioned patent, have, however, created a demand for projection lamps for use therein but, obviously, by reason of the peculiar form of the annulus employed, the commercial type of 40 projection lamp, such as the one above mentioned, having fins, cannot be used in the sockets of housings of constructions such as that shown in the patent above mentioned.

It is an object of the present invention to pro- 45 vide an adapter whereby a projection lamp of the fin type may be used in sockets constructed to receive a different type of lamp.

Another object of the invention is to provide a. simple and efifective adapter which may be 50 quickly and conveniently applied to a lamp base.

Another object of the invention is to provide an adapter so constructed and arranged as to hold a lamp in a socket by engagement with fins projecting radially from the lamp base.

65 Other objects and advantages of the invention will be more clearly understood by reference to the following description together with the accompanylng drawing in which Fig. 1 is a side elevational view of a lamp housing or chamber shown in cross section with a" projection lamp held therein by an adapter constructed in accordance with the present invention; I

Fig. 2 is a view taken on line II-Ii in Fig. 1 with the lamp removed; Fig. 3 is a perspective view of an adapter for holding a lamp in the socket; Fig. 4 is a perspective fragmentary view of a projection lamp showing abase having extensions or fins secured to the base.

Fig. 5 is a fragmentary detailed view of a portion of the adapter showing a lamp base fin disposed inposition and held by a resilient member.

Although the present form of adapter may find use in other forms of sockets or housings, it is particularly adapted for use in a light unit, as shown in Fig. 1, comprising a cylindrical casing 10 which constitutes the main portion of a lamp chamber. Secured to the lower end of the casing is a socket H which socket constitutes the lower portion or bottom of the lamp chamber. The socket may comprise a tubular body portion I2 made of any suitable insulative material. The interior of the tubular casing communicates with the lamp chamber. The body portion I2 is provided with an annular contact member or ring i3 which is imbedde in and extends from the interior surface of the tubular body l2. This annular contact is provided with a foot piece M to which may be secured an electrical conductor I5. The foot piece I4 of the contact I3 is disposed in a recess iii in the outer wall of the tubular body l2.

Another recess l! is provided in the outer wall of the body l2 to accommodate a foot piece I8 which is integral with and extends from a metallic collar I9. The outer surface of the collar l9 fits a counter-bore portion of the tubular body l2. A conductor 2| is suitably connected with the foot piece l8 and a cover plate 22, provided with apertures through which the'conductors' l5 and 2| extend, is secured to the tubular body l2. The 'metallic collar serves as a conductor member and its interior surface is threaded to receive an externally threaded cup-shaped member 23 which is secured to a disc 24 of insulative material provided with a projection or finger piece 25 which constitutes a closure 25' for the lower end of the tubular body through which a lamp may be inserted or removed. The cup-shaped member 23 relative rotary movement in the socket.

The present invention aims to provide an adapter which makes it possible to accurately support a projection lamp having a base with fins, such as shown in Fig. 4. This lamp may oomprise a bulb 29 havingmounted therein the usual filamentary light source 29 supported from a press 3!. The bulb is provided with a base 32 which base is applied to the bulb with the usual manufacturing accuracy. This base is then inserted into an outer or secondary base 33 having extensions or fins 34. While the secondary base is free to move relative to the primary base, it is adjusted until the fins 34 are a predetermined distance from the center of the light source 29. When so adjusted the secondary base is secured by solder 35 to the primary base.

A projection lamp so constructed is then ready to be inserted into fixtures arranged to engage the fins. When it is desirable to use this type of lamp in a base, such as shown in Fig. 1, however, an adapter 39, as more clearly shown in'Fig. 3, is employed. This adapter is of tubular form to slidably fit the cylindrical secondary base 33 and is provided with an annulus or flange 31 externally extending from one edge thereof. This flange is provided with a seat 39 so proportioned as to receive and accommodate the fins 34. Above the seat for the fins andat opposite sides of the upper edge of the adapter are disposed arcuate shaped retainer arms 39. These arms are disposed in such spaced relation to the seat 39 as to provide slots 4|.

Each of the arms 39 extend only part way around the edge of the seat so that lamps may be first positioned with the fins on the surface 42 and by rotating the lamp in the direction of the arrow X, the fins may be moved beneath the arms.

In the lamp housing, as shown in Fig. 1, the annular contact i3 is positioned a definite distance from a point on the casing so that when a lamp is in position the light source will be disposed in a predetermined position with respect to a reflector or lens. The adapter constructed in accordance with my invention is so constructed that the normal upper surface of the flange 31 engages the under surface of the contact l3. The arms 39, which extend above the seat 42, are

so arranged that their lower surfaces are a given distance from the focal point in the housing and when the upper surfaces of the fins 34 engage the lower surfaces of the arms 39 the light source 29 will be properly disposed for the effective projection of a beam of light. As above mentioned, the

. fins are positioned on the base a definite and predetermined distance from a point in the filament 29. when a lamp having by adapter applied thereto is disposed in a housing the tension member 29 serves to press the lamp upwardly and maintain the fins in their proper contact relation with the arms 39. In some housings the tension members may not be of sufllcient strength to hold the fins'and arms in the desired contact relation in which case the adapter may, as shown in Fig. 5, be provided with a spring member 49 which serves to press the fins against the arms 39. The members may be formed with inclined portions 40' which, in oonjunctian with inclined surfaces except with the filament in a definite position determined by the position of the fins.

For the purpose of positioning a lamp having the adapter applied thereto in a predetermined position in the socket, the adapter is provided with a lug 43 proportioned to enter the notch 21. As shown in Fig. 1, a lamp, with an adapter thereon, may be inserted through the bottom of the tubular body l2 by first removing the closure 25'. When a lamp is in position the annulus 31 will engage the contact ring l3 and when the lower end of the tubular body is closed the resilient member 26 will engage the bottom contact on the lamp and hold the annulus in firm engagement with the contact l3. The lug 43, being disposed in the notch 21, prevents relative rotary movement of the lamp.

When a lamp is held in an adapter electrical 25 energy may fiow through the conductor 2|, through the metallic parts of the socket and into the lamp through the lower bottom contact thereof. The return flow, will, obviously, occur by means of the electrical contact between the base and the adapter which engages the contact ring l3, the latter being electrically connected with the conductor l5.

It will be evident that, by reason of the present invention, a lamp provided with a secondary base, having extensions or fins thereon, may be easily and quickly provided with an adapter making it possible to use this type of lamp in sockets where heretofore it was necessary to provide a lamp with a special form of base. The adapter, as con structed in accordance with the present invention, is of simple design and may be readily cast or turned from a single piece of metal making the adapter of relatively low cost and of considerable advantage to the users of sockets especially designed for special forms of lamps.

Although a preferredembodiment of the invention is shown and described herein, it is to be understood that modifications may be made therein without departing from the spirit and scope of the invention as set forth in the appended claims.

What is claimed is:

1. In combination with an incandescent electric lamp base having a flange extending therefrom, an adapter, comprising, a tubular member having an inside diameter so proportioned as to slidebly fit the outer surface of the base, a contact member extending from the outer surface of said tubular member to engage a contact in a socket, and an arcuate arm spaced from an edge of said so tubular member for holding said flange of said lamp base relative to said tubular member. 7

2. In combination with an incandescent electric lamp base having a laterally extending fin, an adapter comprising, a tubular member to receive 65 said base with the fin thereof adjacent to one-edge of, said member, an arm extending above and along said edge to hold said fin in spaced'relation to said edge and a lateral projection extending from the exterior surface of said tubular member. 70

3. In combination with an incandescent electric lamp base having a laterally extending flange, an adapter comprising a tubular body to receive a base, a seat for said flange at one edge of said body. an arm above and spaced from said seat and 75 resilient means between said arm and seat for slots open at opposite ends adjacent to one edge retaining said flange in contact with said arm. thereof to receive said fins upon a rotation of said 4. In combination with anincandescent electric lamp when the base portion is disposed in said lamp base having laterally projecting fins on the tubular body and an annular contact member 5 base thereof, an adapter comprising a tubular extending from the exterior surface oisaid body. 5

body to receive said base, said body having lateral .EUGENE W. BEGGS. 

